ABSTRACT
Dexrazoxane (ICRF-187) has been clinically used to reduce doxorubicin-induced cardiotoxicity for more than 20 years. It has been proposed that dexrazoxane may act through its rings-opened hydrolysis product ADR-925, which can either remove iron from the iron-doxorubicin complex or bind to free iron, thus preventing iron-based oxygen radical formation. However, it is not known whether the antioxidant actions of dexrazoxane are totally dependent on its metabolization to its rings-opened hydrolysis product and whether dexrazoxane has any effect on the iron-independent oxygen free radical production. In this study, we examined the scavenging effect of dexrazoxane on hydroxyl, superoxide, lipid, DPPH and ABTS(+) free radicals in vitro solution systems. The results demonstrated that dexrazoxane was an antioxidant that could effectively scavenge these free radicals and the scavenging effects of dexrazoxane did not require the enzymatic hydrolysis. In addition, dexrazoxane was capable to inhibit the generation superoxide and hydroxyl radicals in iron free reaction system, indicating that the antioxidant properties of dexrazoxane were not solely dependent on iron chelation. Thus the application of dexrazoxane should not be limited to doxorubicin-induced cardiotoxicity. Instead, as an effective antioxidant that has been clinically proven safe, dexrazoxane may be used in a broader spectrum of diseases that are known to be benefited by antioxidant treatments.
ABSTRACT
About 70% of Parkinson's pathogenesis comes from environment factor and one important of which is oxidative stress although the genetic factor plays an important role. The antioxidant of green tea polyphenols(GTP) and they can enter into plasma even penetrate blood brain barie provides an important condition for the protective effects of GTP against Parkinson's Disease(PD). In cellular model the protective mechanisms of GTP on PC12 and SH-SY5Y cells against apoptosis induced by 6-hydroxydopamine (6-OHDA) were investigated. GTP attenuated 6-OHDA-induced early apoptosis, prevented the decrease in mitochondrial membrane potential, suppressed accumulation of reactive oxygen species (ROS) and of intracellular free Ca2+. GTP also counteracted 6-OHDA-induced nitric oxide increase and over-expression of nNOS and iNOS, and decreased the level of protein bound 3-Nitro-tyrosine (3-NT). Using PD rat model injected by 6-OHDA, the effect of GTP were investigated on animal model. Results showed that GTP attenuated the injury in a dose and time dependent manner. Pretreatment of the animals with GTP decreased ROS and NO production, thiobarituric acid reactive substances content, nitrite/nitrate concentration, and protein bound 3-Nitro-tyrosine (3-NT) in brain homogenate of midbrain and striatum in a concentration and time dependent manner. NOS participated in the neuron death induced by 6-OHDA and it was found that the pretreatment with GTP could decrease the protein level of nNOS and iNOS. More neurons survived and less cells suffered apoptosis in the substantia nigra pars compacta (SNc) of GTP treated animal brain. These results suggest that oral administration of GTP increases the antioxidant level in the brain and protects the brain against cell death caused by 6-OHDA. The experimental results of present study support the neuroprotection of GTP and provided new strategy of preventing and curing Parkinson's diseases by ROS-NO pathway.
ABSTRACT
A set of plate form three-dimensional magnetic gradient coils was developed and used in electron spin resonance imaging (ESRI) experiment. The coils were processed with whole copper plates instead of wound with copper wires, which made its structure so compact that it was much thinner and smaller comparing to those traditionally used in ESRI. The coil set had a pie-like appearance of which the total thickness was only 14 mm and the outer diameter was 250 mm. The efficiency of the coils could be greater than 10 mT/m/A when distance between the two side-pieces was 63 mm. A maximum gradient strength of more than 200 mT/m could be obtained with driving current of about 20 A in each dimension coil. The spatial linearity was better than 5% in all three dimensions within the available spatial linearity area of larger than a sphere of 40 mm in diameter. The stability of the gradients strength could reach the level of 10(-5). An imaging resolution of better than 1 mm could be achieved with the coil set. Some preliminary practical imaging results show that the developed gradient coil set is suitable for L-band ESRI experiment of biological samples or even in vivo small animals.
Subject(s)
Electron Spin Resonance Spectroscopy/instrumentation , Animals , Copper , Equipment Design , MiceABSTRACT
AimTo investigate the influence of tetramethylpyrazine(ligustrazine, Lig) on oxygen consumption and superoxide during the respiratory burst of human neutrophils. MethodsIt was observed by using ESR spin trapping, spin probe oxymetry and luminol-dependent chemiluminesence(CL) . Results Lig had no influence on oxygen consumption during the respiratory burst of neutrophils(P＞0.05), but had remarkable inhibition on CL response generated by neutrophils(P＜0.01), and had scavenging effect on O2 and OH ·generated by neutrophils, which were demonstrated in xanthine/ xanthine oxidase system and Fentons reaction(P＜0.01) . ConclusionLig has no inhibiting effect on oxygen metabolic function of neutrophils,but protects tissue from injury caused by activated neutrophils through scavenging oxygen radicals.
ABSTRACT
The extraction method with organic solvent extraction to detect nitric oxide was improved, and the production of nitric oxide in mice myocardium in vitro was detected with this method. Using organic solvent (DETC)2-Fe2 + -NO complex was extracted from water phase into ester phase, and nitric oxide in sample of large volume can be detected by ESR at room temperature. The extracting ability of several organic solvents such as ethyl acetate, butyl acetate, glycerol triacetate, iso-amy lacetate, and n-butanol, was compared, and it was found that ethyl acetate was a good kind of organic solvent. There was a good linear relationship between the concentration of nitric oxide and ESR intensity within concentration of 20μmol/L, and the detected limit was improved to below 200 nmol/L; (DETC)2-Fe2+ -NO complex is easy to decompose in light but it is very stable in dark at 0～4℃ which, there is only a little change after ten days.
ABSTRACT
The scavenging effects of Total Flavonoids of Hippophae ( TFH ) were studied by using ESR-spin trapping technique in different systems, and the inhibitery effects on chemiluminescence ( CL ) of poly-morphonuclear leukocytes ( PMN) were measured by using luminol-de-pendent CL. TFH ( 1.7mg/L ) significantly reduced the active oxygen radicals level of PMA-stimulated PMN; TFH ( 0.03-3mg/L ) could remarkably scavenged O2 in xanthine/xanthine oxidase (Xan/XO)system and the effect was concentration-dependent. The scavenging effect of TFH on O2 in irradiation riboflavin system was not so strong as in Xan/XO system. TFH ( 3 mg/L ) could scavenged OH produced in Fenton's reaction; TFH ( 1 mg/L ) effectively inhibited PMN CL stimulated by PMA.The effects of TFH on active oxygen radicals produced by PMN and O2 in Xan/XO system were stronger than Vit E.
ABSTRACT
Using Xanthine-Xanthine Oxidase system to generate superoxide ani-on, using H2O2 -Fe2 + system to generate hydroxyl radical, the role of scavenging oxygen free radical by Miltiorrhiza was studied by electron paramagnetic resonance and spin trapping. The result suggested that the scavenging rate of hydroxyl radical by Salvia Miltiorrhiza injection is 65%, and that of superoxide anion is 100%. This result suggests that scavenging cytotoxic oxygen free radicals may be one of important pharmacological mechanism of Salvia Miltiorrhiza.
